Our Oceans Are Going ‘Nuclear' Because of Climate Change

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M ath can be scary, but if you’re in the market for some really terrifying mathematics, a major new study puts hard numbers to the rate at which oceans are heating up due to global warming. Hold on to your exponential functions.

According to research published this week in the journal Proceedings of the National Academy of Sciences, the world’s oceans are absorbing around 90 percent of the excess energy caused by greenhouse gas emissions. That’s to say that the bulk of global warming is sinking into the world’s oceans, increasing temperatures and triggering sea level rise worldwide.

The compiled estimates suggest that global warming of the oceans from 1871 to the present adds up to about 436 x 1021 Joules.Unless you speak math, that might not mean much, so researchers have provided some context. The excess heat absorbed by the oceans in that time frame is around 1,000 times the annual energy use of the entire population of Earth.

For a more vivid analogy, the science team at The Guardiancrunched the numbers with a different metric in mind. Global warming, it concluded, has heated the oceans by the equivalent of one atomic bomb explosion per second for the past 150 years.

Bracing analogy, isn’t it? The Guardian editors checked their calculations with the lead author of the study, Laure Zanna of the University of Oxford, and got no argument from the veteran climate physicist.

“I try not to make this type of calculation, simply because I find it worrisome,” Zanna told The Guardian. “We usually try to compare the heating to [human] energy use, to make it less scary.”

Hoo boy.

These new estimates support evidence that the oceans are absorbing most of the excess energy in the climate system.

Compiled by an international group of scientists, the new study employed techniques from an array of disciplines, including physics, mathematics, earth science, and climatology. The basic approach was to take the combined worldwide measurements of ocean temperatures since 1871, then run that data through the latest computer models of ocean circulation patterns to find where all the heat has gone.

Developed by researcher Samar Khatiwala, the technique uses blunt force mathematics to assess global ocean warming down to the seabed.

“Our approach is akin to ‘painting’ different bits of the ocean surface with dyes of different colors and monitoring how they spread into the interior over time,” Khatiwala said in a statement issued with the new research. “If we know what the sea surface temperature anomaly was in 1870 in the North Atlantic Ocean we can figure out how much it contributes to the warming in, say, the deep Indian Ocean in 2018.”

The distressing upshot is that, according to the research team, these new estimates support evidence that the oceans are absorbing most of the excess energy in the climate system, which is produced from greenhouse gases emitted by human activities.

The really important part, for those of us who live in threatened coastal areas, is that warmer oceans mean rising sea levels that are compounded by the physical expansion of water as it gets warmer. In other words, those melting ice caps are only part of the problem.

The new research should help scientists make more accurate predictions in the years to come of where and when sea levels will rise. Presumably, this will be useful to us survivors paddling around in the floating city of New Topeka.